Spider

A spider is a wall-climbing neutral arthropod (arachnid) that attacks players on sight in dark areas by jumping and biting them. They drop string and spider eyes on death.

Spiders can spawn in the Overworld at a light level of 0 within a 3×1×3 space centered on an opaque block. In Java Edition, the block above the spawning space cannot be a full solid block, including transparent ones such as leaves or glass, but non-full blocks, such as soul sand or slabs, are allowed.[1] Spiders do not spawn in mushroom fields and deep dark biomes, and they are replaced by cave spiders in sulfur caves. In Bedrock Edition, spiders also do not spawn in rivers, frozen rivers, and snowy plains and do not spawn in groups.

Spiders spawn from monster spawners found in monster rooms (25% chance) as well as in secret rooms surrounded by cobwebs in woodland mansions.